Details
Minor Description
- Proposal:
#define( $block_ref )
-
- any VTL / text content here
...
#end
- any VTL / text content here
then you can use it like a reference:
<html><body> $!block_ref </body></html> / #if( $block_ref ).. #end / and so on
- Justification:
1. Allows template designer to use a more efficient inside -> out approach
(similar to Nathan's VelocityLayoutServlet)
2. Keeps macro framework separate (the app developer can still disallow inline
macros)
3. #macros to return blocks of VTL cannot be used like silent references or in
other directives (like #if)
4. The multi-line #set proposal requires a quoted value. A #define() block can
contain anything (without the need to escape quotes for example).
5. #define() blocks are proxied (like #macros) and thus change according to the
context after they are defined, something a normal $reference or #set can't do.
7. Can improve template management by reducing number of unique template components
8. Can improve template security/errors by reducing the need for bottom tier
template makers to worry about generic layout code and visa-versa.
9. Merges the strengths of #macros and $references = best of both worlds
- Usage Example: Custom HTML forms:
template 1. : document_type_1_custom_form_body.vm
#define( $custom_form_body )
-
- unique form fields here
#end
#parse("main_form_layout.vm")
template 2 : main_form_layout.vm
#define( $custom_page_body )
<form>
-
- common form fields here
$!custom_form_body
<input type="submit" value="submit">
</form>
#end
#parse("main_page_layout.vm")
template 2 : main_page_layout.vm
<html><body>
-
- common page layout html here
$!custom_page_body
- common page layout html here
</body></html>
If the #define() directive was not available a template designer would need to
do this:
template 1. : document_type_1_custom_form_body.vm
#parse("main_page_layout_header.vm")
#parse("main_form_layout_header.vm")
-
- unique form fields here
#parse("main_form_layout_header.vm")
#parse("main_page_layout_header.vm")
- unique form fields here
Not only is the same output achieved with fewer #parse() directives (3 v 5), the
unique templates are fewer and easier to manage. Template designers can make
many document_type_X templates and need only to define the reference
$custom_form_body and not worry about the overall page layout. Custom parts of
the page are also only optionally required now; the main template can test for a
reference and display a default block if it isn't defined.
Attachments
Attachments
Issue Links
- blocks
-
VELOCITY-583 BlockMacro support
-
- Closed
-